模糊滑模控制 PPT

1.Introduction
Reliability allocation is an important and iterative task during the design and development activities of any engineering system. It is also difficult task because of the obscured and incomplete design details and a number of factors have to consider in design process. During the design phase of a system with a specified target reliability level, the reliability levels of the subsystems affect the overall system reliability. Therefore, a proper reliability allocation method needs to be adopted to allocate the target system reliability to its constituent subsystems proportionately.
quite difficult to further improve the reliability of a component even if the reliability is considerably lower than desired.
Βιβλιοθήκη Baidu
values are known. The relationship between apportioned reliability of ith
subsystem Ri （子系统可靠度）and target system reliability R*（总系统可 靠度） is defined with a weightage factor wi.
1. Multiple functional relationships with the other groups. 2. Number of components comprising subsystem.
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2.2. Cost（成本）
For a large system, the cost increment for reliability improvement is relatively high. The demonstration of a high reliability value for a costly system may be extremely uneconomical.
1.Introduction 2.Factors based conventional reliability allocation method 3.Fuzzy numbers and arithmetic 4.The methodology 5.Illustrative example 6.Conclusions
2.Factors based conventional reliability allocation method
In this allocation method, the target reliability based on the reliability
factors is apportioned to subsystems for which no predicted reliability
Ri= (R*)wi
(1)
where weightage factor wi （权重因子）can be expressed with
proportionality factor Zi（比例因子）as：
wi = Zi /∑Zi
(2)
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2.1. Complexity（复杂度） The complexity factor varies from subsystem to subsystem within a system and is measured in terms of number of active components that a subsystem is composed of. The number of components in a subsystem has a direct bearing on the reliability of the subsystem. Thus, complexity has a strong impact on the reliability allocation. The failure rate of the subsystem with high complexity is generally going to be high. So, the failure rate is allocated proportional to the complexity of the subsystem. Hence, Zi ∝ Ki, where Ki is the complexity factor for the its subsystem.
Hence, Zi ∝Coi, where Coi is the cost factor for the its subsystem.
2.3. State-of-the-art（工艺状态） When the component has been available for a long time, it is
Fuzzy arithmetic based reliability allocation approach during early design and development
初期阶段的设计和发展中基于模糊算法的可靠度分配方法
V. Sriramdas , S.K. Chaturvedi , H. Gargama